<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>前端技术方向</title>
</head>
<body>


<script>
    //断言
    var a=1;
    var b=2;
    console.assert(a==1,"a不等于1");
    console.assert(b==1,"b不等于1");//这一行被输出
    console.log(a,b);

    //性能优化
    console.time("timer");
    for(var i=0;i<10000;i++){}
    console.timeEnd("timer");

</script>
</body>
</html>